Window coverings or blinds such as awnings, mini-blinds, Venetian blinds, or folded blinds generally have two or more lifting cords, one near each end of the blind. One end of each lifting cord is attached to the free end of the blind, while the other end is attached to the lifting mechanism. The lifting mechanism may be as simple as a pull cord and clutch or as complex as a remote controlled motor. No matter what the lifting mechanism is, the owner of the blind desires that the free end of the blind remain level during the winding and unwinding of the blind.
Keeping the free end of the blind level is important both for esthetic and mechanical reasons. If the free end of the blind does not remain level, the most expensive decor may appear cheap. Moreover, this may be a source of irritation for the owner or operator. In addition, the chance that the lifting mechanism will jam or that there will be uneven wear on the mechanism increases when the free end of the blind does not remain level. These problems are multiplied as the length of the blinds increases or as the blinds get wider, which requires more lifting cords to be added.